Prospects of developing a prophylactic vaccine against human lymphatic filariasis - evaluation of protection in non-human primates

Immune targeting of filarial glutaredoxin through a multi-epitope peptide-based vaccine: A reverse vaccinology approach

Despite the efforts of global programme to eliminate lymphatic filariasis (GPELF), the threat of lymphatic filariasis (LF) still looms over humanity in terms of long-term disabilities, and morbidities across the globe. In light of this situation, investigators have chosen to focus on the development of immunotherapeutics targeting the physiologically important filarial-specific proteins. Glutaredoxin (16.43 kDa) plays a pivotal role in filarial redox biology, serving as a vital contributor. In the context of the intra-host survival of filarial parasites, this antioxidant helps in mitigating the oxidative stress imposed by the host immune system. Given its significant contribution, the development of a vaccine targeting glutaredoxin holds promise as a new avenue for achieving a filaria-free world. Herein, multi-epitope-based vaccine was designed using advanced immunoinformatics approach. Initially, 4B-cell epitopes and 6 T-cell epitopes (4 MHC I and 2 MHC II) were identified from the 146 amino acid long sequence of glutaredoxin of the human filarid, Wuchereria bancrofti. Subsequent clustering of these epitopes with linker peptides finalized the vaccine structure. To boost TLR-mediated innate immunity, TLR-specific adjuvants were incorporated into the designed vaccine. After that, experimental analyses confirm the designed vaccine, Vac4 as anefficient ligand of human TLR5 to elicit protective innate immunity against filarial glutaredoxin. Immune simulation further demonstrated abundant levels of IgG and IgM as crucial contributors in triggering vaccine-induced adaptive responses in the recipients. Hence, to facilitate the validation of immunogenicity of the designed vaccine, Vac4 was cloned in silico in pET28a(+) expression vector for recombinant production. Taken together, our findings suggest that vaccine-mediated targeting of filarial glutaredoxin could be a future option for intervening LF on a global scale.

Identification and prioritisation of potential vaccine candidates using subtractive proteomics and designing of a multi-epitope vaccine against Wuchereria bancrofti

This study employed subtractive proteomics and immunoinformatics to analyze the Wuchereria bancrofti proteome and identify potential therapeutic targets, with a focus on designing a vaccine against the parasite species. A comprehensive bioinformatics analysis of the parasite's proteome identified 51 probable therapeutic targets, among which "Kunitz/bovine pancreatic trypsin inhibitor domain-containing protein" was identified as the most promising vaccine candidate. The candidate protein was used to design a multi-epitope vaccine, incorporating B-cell and T-cell epitopes identified through various tools. The vaccine construct underwent extensive analysis of its antigenic, physical, and chemical features, including the determination of secondary and tertiary structures. Docking and molecular dynamics simulations were performed with HLA alleles, Toll-like receptor 4 (TLR4), and TLR3 to assess its potential to elicit the human immune response. Immune simulation analysis confirmed the predicted vaccine's strong binding affinity with immunoglobulins, indicating its potential efficacy in generating an immune response. However, experimental validation and testing of this multi-epitope vaccine construct would be needed to assess its potential against W. bancrofti and even for a broader range of lymphatic filarial infections given the similarities between W. bancrofti and Brugia.

In-silico development of multi-epitope subunit vaccine against lymphatic filariasis

The World Health Organization in 2022 reported that more than 863 million people in 50 countries are at risk of developing lymphatic filariasis (LF), a disease caused by parasitic infection. Immune responses to parasites suggest that the development of a prophylactic vaccine against LF is possible. Using a reverse vaccinology approach, the current study identified Trehalose-6-phosphatase (TPP) as a potential vaccine candidate among 15 reported vaccine antigens for B. malayi. High-ranking B and T-cell epitopes in the Trehalose-6-phosphatase (TPP) were shortlisted using online servers for subsequent analysis. We selected these peptides to construct a vaccine model using I-TASSER and GalaxyRefine server. The vaccine construct showed favorable physicochemical properties, high antigenicity, no allergenicity, no toxicity, and high stability. Structural validation using the Ramachandran plot showed that 98% of the residues were in favorable or mostly allowed regions. Molecular docking and simulation showed a strong binding affinity and stability of the subunit vaccine with toll-like receptor 4 (TLR4). Furthermore, the subunit vaccine showed a strong IgG/IgM response, with the disappearance of the antigen. We propose that our vaccine construct should be further evaluated using cellular and animal models to develop a vaccine that is safe and effective against LF.Communicated by Ramaswamy H. Sarma.

Adjuvanted Fusion Protein Vaccine Induces Durable Immunity to Onchocerca volvulus in Mice and Non-Human Primates

Onchocerciasis remains a debilitating neglected tropical disease. Due to the many challenges of current control methods, an effective vaccine against the causative agent Onchocerca volvulus is urgently needed. Mice and cynomolgus macaque non-human primates (NHPs) were immunized with a vaccine consisting of a fusion of two O. volvulus protein antigens, Ov-103 and Ov-RAL-2 (Ov-FUS-1), and three different adjuvants: Advax-CpG, alum, and AlT4. All vaccine formulations induced high antigen-specific IgG titers in both mice and NHPs. Challenging mice with O. volvulus L3 contained within subcutaneous diffusion chambers demonstrated that Ov-FUS-1/Advax-CpG-immunized animals developed protective immunity, durable for at least 11 weeks. Passive transfer of sera, collected at several time points, from both mice and NHPs immunized with Ov-FUS-1/Advax-CpG transferred protection to naïve mice. These results demonstrate that Ov-FUS-1 with the adjuvant Advax-CpG induces durable protective immunity against O. volvulus in mice and NHPs that is mediated by vaccine-induced humoral factors.

Construction and validation of a multi-epitope in silico vaccine model for lymphatic filariasis by targeting Brugia malayi: a reverse vaccinology approach

BACKGROUND

Lymphatic filariasis (LF), often referred to as elephantiasis, has been identified as one of the 17 neglected tropical diseases by the World Health Organization. Currently, there are no vaccines available to treat this infection in humans. Therefore, with the objective of devising a novel preventive measure, we exploited an immunoinformatics approach to design a multi-epitope-based subunit vaccine for LF, that can elicit a variety of immune responses within the host. In this study, different B cell, T_C cell, and T_H cell-binding epitopes were screened from the antigenic proteins of Brugia malayi and they were passed through several immunological filters to determine the optimal epitopes.

RESULTS

As a result, 15 CD8+, 3 CD4+, and 3 B cell epitopes were found to be prominent, antigenic, non-toxic, immunogenic and non-allergenic. The presence of conformational B cell epitopes and cytokine-inducing epitopes confirmed the humoral and cell-mediated immune response that would be triggered by the constructed vaccine model. Following that, the selected epitopes and TLR-4-specific adjuvant were ligated by appropriate peptide linkers to finalize the vaccine construct. Protein-protein docking of the vaccine structure with the TLR4 receptor predicted strong binding affinity and hence putatively confirms its ability to elicit an immune response. Further, the efficiency of the vaccine candidate to provide a long-lasting protective immunity was assessed by in silico immune simulation. The reverse translated vaccine sequence was also virtually cloned in the pET28a (+) plasmid after the optimization of the gene sequence.

CONCLUSION

So taken together, by monitoring the overall in silico assessment, we hypothesize that our engineered peptide vaccine could be a viable prophylactic approach in the development of vaccines against the threat of human lymphatic filariasis.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1186/s42269-023-01013-0.

Identification of dynamic gene expression profiles during sequential vaccination with ChAdOx1/BNT162b2 using machine learning methods

To date, COVID-19 remains a serious global public health problem. Vaccination against SARS-CoV-2 has been adopted by many countries as an effective coping strategy. The strength of the body’s immune response in the face of viral infection correlates with the number of vaccinations and the duration of vaccination. In this study, we aimed to identify specific genes that may trigger and control the immune response to COVID-19 under different vaccination scenarios. A machine learning-based approach was designed to analyze the blood transcriptomes of 161 individuals who were classified into six groups according to the dose and timing of inoculations, including I-D0, I-D2-4, I-D7 (day 0, days 2–4, and day 7 after the first dose of ChAdOx1, respectively) and II-D0, II-D1-4, II-D7-10 (day 0, days 1–4, and days 7–10 after the second dose of BNT162b2, respectively). Each sample was represented by the expression levels of 26,364 genes. The first dose was ChAdOx1, whereas the second dose was mainly BNT162b2 (Only four individuals received a second dose of ChAdOx1). The groups were deemed as labels and genes were considered as features. Several machine learning algorithms were employed to analyze such classification problem. In detail, five feature ranking algorithms (Lasso, LightGBM, MCFS, mRMR, and PFI) were first applied to evaluate the importance of each gene feature, resulting in five feature lists. Then, the lists were put into incremental feature selection method with four classification algorithms to extract essential genes, classification rules and build optimal classifiers. The essential genes, namely, NRF2, RPRD1B, NEU3, SMC5, and TPX2, have been previously associated with immune response. This study also summarized expression rules that describe different vaccination scenarios to help determine the molecular mechanism of vaccine-induced antiviral immunity.

Reverse vaccinology assisted design of a novel multi-epitope vaccine to target Wuchereria bancrofti cystatin: An immunoinformatics approach

Proteases are the critical mediators of immunomodulation exerted by the filarial parasites to bypass and divert host immunity. Cystatin is a small (∼15 kDa) immunomodulatory filarial protein and known to contribute in the immunomodulation strategy by inducing anti-inflammatory response through alternative activation of macrophages. Recently, Wuchereria bancrofti cystatin has been discovered as a ligand of human toll-like receptor 4 which is key behind the cystatin-induced anti-inflammatory response in major human antigen-presenting cells. Considering the pivotal role of cystatin in the immunobiology of filariasis, cystatin could be an efficacious target for developing vaccine. Herein, we present the design and in-silico analyses of a multi-epitope-based peptide vaccine to target W. bancrofti cystatin through immune-informatics approaches. The 262 amino acid long antigen construct comprises 9 MHC-I epitopes and MHC-II epitopes linked together by GPGPG peptide alongside an adjuvant (50S ribosomal protein L7/L12) at N terminus and 6 His tags at C terminus. Molecular docking study reveals that the peptide could trigger TLR4-MD2 to induce protective innate immune responses while the induced adaptive responses were found to be mediated by IgG, IgM and Th1 mediated responses. Notably, the designed vaccine exhibits high stability and no allergenicity in-silico. Furthermore, the muti epitope-vaccine was also predicted for its RNA structure and cloned in pET30ax for further experimental validation. Taken together, this study presents a novel multi-epitope peptide vaccine for triggering efficient innate and adaptive immune responses against W. bancrofti to intervene LF through immunotherapy.

Alteration of rhesus macaque serum N-glycome during infection with the human parasitic filarial nematode Brugia malayi

Serum N-glycan profiling studies during the past decades have shown robust associations between N-glycan changes and various biological conditions, including infections, in humans. Similar studies are scarcer for other mammals, despite the tremendous potential of serum N-glycans as biomarkers for infectious diseases in animal models of human disease and in the veterinary context. To expand the knowledge of serum N-glycan profiles in important mammalian model systems, in this study, we combined MALDI-TOF-MS analysis and HILIC-UPLC profiling of released N-glycans together with glycosidase treatments to characterize the glycan structures present in rhesus macaque serum. We used this baseline to monitor changes in serum N-glycans during infection with Brugia malayi, a parasitic nematode of humans responsible for lymphatic filariasis, in a longitudinal cohort of infected rhesus macaques. Alterations of the HILIC-UPLC profile, notably of abundant structures, became evident as early as 5 weeks post-infection. Given its prominent role in the immune response, contribution of immunoglobulin G to serum N-glycans was investigated. Finally, comparison with similar N-glycan profiling performed during infection with the dog heartworm Dirofilaria immitis suggests that many changes observed in rhesus macaque serum N-glycans are specific for lymphatic filariasis.

Pre-clinical development of a vaccine for human lymphatic filariasis

This study was conducted to optimize a fusion protein vaccine for translational development as a vaccine against the human tropical parasitic infection, lymphatic filariasis (LF). The vaccine candidate, His-tagged rBmHAXT was developed previously in our laboratory and was tested in various animal models including mouse, gerbils and Rhesus macaque where it exhibited significant levels of vaccine-induced protection. However, for commercial manufacturing and for regulatory approval for human use, there was a need to modify the vaccine antigen and its production and analytical release methods. Therefore, the major focus of this study was to develop a process for manufacturing an affinity tag-free rBmHAXT and evaluate its immunogenicity, potency and protective efficacy in both inbred and outbred mouse models, as well as in outbred gerbil models. Our results demonstrate that the tag-free rBmHAXT vaccine produced with a process suitable for cGMP production had protective properties equivalent to the original His-tagged rBmHAXT.

Harnessing Immune Evasion Strategy of Lymphatic Filariae: A Therapeutic Approach against Inflammatory and Infective Pathology

Human lymphatic filariae have evolved numerous immune evasion strategies to secure their long-term survival in a host. These strategies include regulation of pattern recognition receptors, mimicry with host glycans and immune molecules, manipulation of innate and adaptive immune cells, induction of apoptosis in effector immune cells, and neutralization of free radicals. This creates an anti-inflammatory and immunoregulatory milieu in the host: a modified Th2 immune response. Therefore, targeting filarial immunomodulators and manipulating the filariae-driven immune system against the filariae can be a potential therapeutic and prophylactic strategy. Filariae-derived immunosuppression can also be exploited to treat other inflammatory diseases and immunopathologic states of parasitic diseases, such as cerebral malaria, and to prevent leishmaniasis. This paper reviews immunomodulatory mechanisms acquired by these filariae for their own survival and their potential application in the development of novel therapeutic approaches against parasitic and inflammatory diseases. Insight into the intricate network of host immune-parasite interactions would aid in the development of effective immune-therapeutic options for both infectious and immune-pathological diseases.

Mass spectrometric and glycan microarray-based characterization of the filarial nematode Brugia malayi glycome reveals anionic and zwitterionic glycan antigens

Millions of people worldwide are infected with filarial nematodes, responsible for lymphatic filariasis (LF) and other diseases causing chronic disablement. Elimination programs have resulted in a substantial reduction of the rate of infection in certain areas creating a need for improved diagnostic tools to establish robust population surveillance and avoid LF resurgence. Glycans from parasitic helminths are emerging as potential antigens for use in diagnostic assays. However, despite its crucial role in host–parasite interactions, filarial glycosylation is still largely, structurally, and functionally uncharacterized. Therefore, we investigated the glycan repertoire of the filarial nematode Brugia malayi. Glycosphingolipid and N-linked glycans were extracted from several life-stages using enzymatic release and characterized using a combination of MALDI-TOF-MS and glycan sequencing techniques. Next, glycans were purified by HPLC and printed onto microarrays to assess the host anti-glycan antibody response. Comprehensive glycomic analysis of B. malayi revealed the presence of several putative antigenic motifs such as phosphorylcholine and terminal glucuronic acid. Glycan microarray screening showed a recognition of most B. malayi glycans by immunoglobulins from rhesus macaques at different time points after infection, which permitted the characterization of the dynamics of anti-glycan immunoglobulin G and M during the establishment of brugian filariasis. A significant level of IgG binding to the parasite glycans was also detected in infected human plasma, while IgG binding to glycans decreased after anthelmintic treatment. Altogether, our work identifies B. malayi glycan antigens and reveals antibody responses from the host that could be exploited as potential markers for LF.

•

Antigenic B. malayi N-linked and GSL glycans were structurally defined.

•

IgG/IgM is induced to a subset of B. malayi glycans upon infection of rhesus macaques.

•

Preferential IgG response to B. malayi glycans observed in chronically infected humans.

•

Marked drop of anti-glycan IgG following treatment of individuals with anthelminthic.

Lymphatic filariasis vaccine development: neglected for how long?

INTRODUCTION

Lymphatic filariasis (LF), also known as elephantiasis, has been recognized by the world health organization and the centers for disease control and prevention as one of the neglected tropical diseases. The huge prevalence and risk of manifestation to date reflect the poor management of this disease. The disease poses vast public health and socio-economic burdens and generates a dire need for the development of a prophylactic solution for mass administration.

AREAS COVERED

Vaccination has been a sought-out strategy for dealing with ever-evolving infectious diseases and can be duly tuned to become a cost effective means of disease control and eventual eradication. In this review, we highlight the epidemiology of LF with the current diagnosis and treatment modules. The need for the development of a potential vaccine candidates, and challenges are discussed. The evidence presented in this review aims to enlighten the readers regarding the essential factors governing LF and its management using prophylactic measures.

EXPERT OPINION

The complex nature of filarial parasites is evident from the absence of a single vaccine for LF. The development and selection of an appropriate preclinical model and its translation into clinical practice is deemed to be a major task needing in-depth evaluation to formulate an effective vaccine. Explorations of the existing vaccine platforms would serve to be an apt strategy in this direction.

Highlighting the Relevance of CD8+ T Cells in Filarial Infections

The T cell immune responses in filarial infections are primarily mediated by CD4+ T cells and type 2-associated cytokines. Emerging evidence indicates that CD8+ T cell responses are important for anti-filarial immunity, however, could be suppressed in co-infections. This review summarizes what we know so far about the activities of CD8+ T cell responses in filarial infections, co-infections, and the associations with the development of filarial pathologies.

Promising Technologies in the Field of Helminth Vaccines

Helminths contribute a larger global burden of disease than both malaria and tuberculosis. These eukaryotes have caused human infections since before our earliest recorded history (i.e.: earlier than 1200 B.C. for Schistosoma spp.). Despite the prevalence and importance of these infections, helminths are considered a neglected tropical disease for which there are no vaccines approved for human use. Similar to other parasites, helminths are complex organisms which employ a plethora of features such as: complex life cycles, chronic infections, and antigenic mimicry to name a few, making them difficult to target by conventional vaccine strategies. With novel vaccine strategies such as viral vectors and genetic elements, numerous constructs are being defined for a wide range of helminth parasites; however, it has yet to be discussed which of these approaches may be the most effective. With human trials being conducted, and a pipeline of potential anti-helminthic antigens, greater understanding of helminth vaccine-induced immunity is necessary for the development of potent vaccine platforms and their optimal design. This review outlines the conventional and the most promising approaches in clinical and preclinical helminth vaccinology.

Filariasis and transfusion-associated risk: a literature review

BACKGROUND AND OBJECTIVES

Filariae are parasitic worms that include the pathogens Loa loa, Onchocerca volvulus, Wuchereria bancrofti, Brugia spp. and Mansonella spp. which are endemic in parts of Africa, Asia, Asia-Pacific, South and Central America. Filariae have a wide clinical spectrum spanning asymptomatic infection to chronic debilitating disease including blindness and lymphedema. Despite successful eradication programmes, filarial infections remain an important -albeit neglected - source of morbidity. We sought to characterize the risk of transfusion transmission of microfilaria with a view to guide mitigation practices in both endemic and non-endemic countries.

MATERIALS AND METHODS

A scoping review of scientific publications as well as grey literature was carried out by a group of domain experts in microbiology, transfusion medicine and infectious diseases, representing the parasite subgroup of the International Society of Blood Transfusion.

RESULTS

Cases of transfusion-transmitted filariasis are rare and confined to case reports of variable quality. Transfusion-associated adverse events related to microfilariae are confined to isolated reports of transfusion reactions. Serious outcomes have not been reported. No known strategies have been implemented, specifically, to mitigate transfusion-transmitted filariasis yet routine blood donor screening for other transfusion-transmissible infections (e.g. hepatitis B, malaria) may indirectly defer donors with microfilaremia in endemic areas.

CONCLUSION

Rare examples of transfusion-transmitted filariasis, without serious clinical effect, suggest that filariasis poses low transfusion risk. Dedicated mitigation strategies against filarial transfusion transmission are not recommended. Given endemicity in low-resource regions, priority should be on the control of filariasis with public health measures.

Fecundity of adult female worms were affected when Brugia malayi infected Mongolian gerbils were immunized with a multivalent vaccine (rBmHAXT) against human lymphatic filarial parasite

A multivalent recombinant fusion protein prophylactic vaccine, rBmHAXT developed against lymphatic filariasis (LF) demonstrated over 57% protection against challenge infection in rhesus macaque model. Currently, we do not know if the rBmHAXT vaccination has any effect on adult worms and/or on the fecundity of adult female worms. Thus, the major focus of this study was to determine the effect of rBmHAXT vaccination on Brugia malayi infected mongolian gerbils. We performed two sets of experiments. In the first set of experiment, gerbils were infected with 100 B. malayi L3. After confirming the establishment of infection, four rounds of DEC treatment and rBmHAXT vaccination was given. Results showed that following vaccination with rBmHAXT, the microfilaria (Mf) count was significantly decreased in all vaccinated animals compared to controls. At the end of these experiments, we collected and counted the established adult worms. There was a 36% reduction in the recovery of adult female worms, which might account for the low Mf load in vaccinated animals. In the second set of experiments, animals were vaccinated first with rBmHAXT followed by surgically implanting adult male or female B. malayi parasites into the peritoneal cavity to determine the effect of vaccination on each sex of the parasite. Our results show that the rBmHAXT vaccination has no effect on male adult worms compared to controls. However, there was 40% reduction in the Mf load in vaccinated animals that were transplanted with adult female worms. These findings suggested that the rBmHAXT vaccination has potential damaging effect on the fecundity of adult female worms. Scanning electron microscopy studies showed cuticular damage on the surface of adult female worms. These studies thus show that the rBmHAXT vaccination in infected gerbils has partial microfilaricidal effect and potentially affect the fecundity of adult female worms.

Advances in Vaccine Development for Human Lymphatic Filariasis

According to the World Health Organization, over 880 million people are currently at risk of acquiring lymphatic filariasis (LF) in over 52 countries worldwide. Current approaches to control LF by 2020 are short of the anticipated goal. Several studies suggest the existence of protective immunity against LF in humans. Thus, it is possible to develop a prophylactic vaccine against LF in humans. Several potential vaccine candidates were identified and tested for their potential against LF. To date, preclinical studies suggest that it is possible to develop a prophylactic vaccine against LF. Much work needs to be done, but it is clear that a prophylactic vaccine, combined with targeted chemotherapy, is critically required for eliminating LF worldwide.

Troponin 1 of human filarial parasite Brugia malayi: cDNA cloning, expression, purification, and its immunoprophylactic potential

In the search for immunoprophylactics for the control of human lymphatic filariasis, we recently identified troponin 1 (Tn1) in Brugia malayi adult worms. The present study reports the cloning and expression of the B. malayi Tn1 (Tn1bm), its immunoprophylactic efficacy against B. malayi infection, and the immunological responses of the host. The Tn1bm gene was cloned (Acc no. JF912447) and expressed, and the purified recombinant Tn1bm (rTn1bm) presented a single ~ 27 kDa band. Parasite load in rTn1bm-immunized BALB/c mice challenged with B. malayi infective larvae (L₃) was assessed. In rTn1bm-immunized animals, IgE, IgG, and IgG subclasses in the serum, cell proliferative response, Th1 and Th2 cytokine secretion (from splenocytes), and NO release (from peritoneal macrophages) were determined. Antibody-dependent cell-mediated cytotoxicity (ADCC) to L₃ was assayed using rTn1bm-immune serum. The innate immune response markers MHC class-I, MHC class-II, TLR2, TLR4, and TLR6 expression in peritoneal macrophages and CD3+, CD4+, CD8+, and CD19+ in the splenocyte population were determined in Tn1bm-exposed cells from naïve mice. rTn1bm-immunized L₃-challenged animals showed a 60% reduction in parasite burden. Immunization upregulated cellular proliferation, cytokine (IFN-γ, TNF-α, IL-1β, IL-4, IL-6, and IL-10) secretion, NO release, and antigen-specific IgG, IgG1, and IgG2b antibody levels. rTn1bm-immune serum killed > 65% of L₃ in the ADCC assay. Increased MHC class-II, TLR2, and TLR6 expression and the relative CD4+ and CD19+ cell populations of naïve animal cells indicated the ability of rTn1bm to mobilize innate immune responses. This is the first report of the immunoprophylactic potential of rTn1bm against B. malayi.

Alpha7 nAChR Expression Is Correlated with Arthritis Development and Inhibited by Sinomenine in Adjuvant-Induced Arthritic Rats

Sinomenine (SIN) is the active ingredient of the Chinese herb Sinomenium acutum that has been used to treat rheumatoid arthritis (RA) for about 30 years in China. Marked expression of the alpha7 nicotinic acetylcholine receptor (α7nAChR) in the joint synovium of RA patients suggested a relationship between α7nAChR and RA. This study investigated the relationship between α7nAChR and RA development and the effects of SIN on α7nAChR expression in vivo and in vitro. Sprague-Dawley rats were injected with complete Freund's adjuvant to induce arthritis and then treated with SIN or methotrexate (MTX) from day 0 to day 30. Four clinical parameters-paw volume, arthritic index (AI), serum TNF-α concentration, and erythrocyte sedimentation rate (ESR)-were measured. Splenic lymphocytes were isolated for Bacille Calmette Guerin (BCG) stimulation. α7nAChR expression in tissues and cells was examined by RT-PCR, western blot, immunofluorescence, flow cytometry, and immunohistochemistry. Cell proliferation was evaluated by the CCK-8 assay. The relationship between α7nAChR expression and the four clinical parameters was analyzed by single-factor correlation analysis. Our results showed that the paw volume, AI, TNF-α concentration, and ESR in adjuvant-induced arthritic (AIA) rats were reduced by SIN or MTX treatment. SIN decreased α7nAChR expression in tissues and cells compared to the model group, while MTX had no significant effect on α7nAChR expression. Moreover, there was a positive relationship between α7nAChR expression and paw swelling, AI, and TNF-α concentration. Splenic lymphocyte activation was accompanied by increased α7nAChR expression, while SIN treatment inhibited cell activation and downregulated α7nAChR expression. α7nAChR expression showed a positive correlation with the progression of RA in AIA rats that may involve lymphocyte activation. Different from MTX, the inhibition of SIN on α7nAChR expression might contribute to its antiarthritic effect, suggesting that SIN could be an important supplement to the treatment strategy for RA.